// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
package qunar.tc.decompiler.modules.decompiler.sforms;

import qunar.tc.decompiler.code.CodeConstants;
import qunar.tc.decompiler.modules.decompiler.exps.AssignmentExprent;
import qunar.tc.decompiler.modules.decompiler.exps.Exprent;
import qunar.tc.decompiler.modules.decompiler.exps.FunctionExprent;
import qunar.tc.decompiler.modules.decompiler.exps.VarExprent;
import qunar.tc.decompiler.modules.decompiler.sforms.FlattenStatementsHelper.FinallyPathWrapper;
import qunar.tc.decompiler.modules.decompiler.stats.CatchAllStatement;
import qunar.tc.decompiler.modules.decompiler.stats.CatchStatement;
import qunar.tc.decompiler.modules.decompiler.stats.RootStatement;
import qunar.tc.decompiler.modules.decompiler.stats.Statement;
import qunar.tc.decompiler.modules.decompiler.vars.VarVersionPair;
import qunar.tc.decompiler.struct.StructMethod;
import qunar.tc.decompiler.struct.gen.MethodDescriptor;
import qunar.tc.decompiler.util.FastSparseSetFactory;
import qunar.tc.decompiler.util.FastSparseSetFactory.FastSparseSet;
import qunar.tc.decompiler.util.InterpreterUtil;
import qunar.tc.decompiler.util.SFormsFastMapDirect;

import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map.Entry;

public class SSAConstructorSparseEx {

    // node id, var, version
    private final HashMap<String, SFormsFastMapDirect> inVarVersions = new HashMap<>();

    // node id, var, version (direct branch)
    private final HashMap<String, SFormsFastMapDirect> outVarVersions = new HashMap<>();

    // node id, var, version (negative branch)
    private final HashMap<String, SFormsFastMapDirect> outNegVarVersions = new HashMap<>();

    // node id, var, version
    private final HashMap<String, SFormsFastMapDirect> extraVarVersions = new HashMap<>();

    // (var, version), version
    private final HashMap<VarVersionPair, FastSparseSet<Integer>> phi = new HashMap<>();

    // var, version
    private final HashMap<Integer, Integer> lastversion = new HashMap<>();

    // set factory
    private FastSparseSetFactory<Integer> factory;

    public void splitVariables(RootStatement root, StructMethod mt) {

        FlattenStatementsHelper flatthelper = new FlattenStatementsHelper();
        DirectGraph dgraph = flatthelper.buildDirectGraph(root);

        // try {
        // DotExporter.toDotFile(dgraph, new File("c:\\Temp\\gr12_my.dot"));
        // } catch(Exception ex) {ex.printStackTrace();}

        HashSet<Integer> setInit = new HashSet<>();
        for (int i = 0; i < 64; i++) {
            setInit.add(i);
        }
        factory = new FastSparseSetFactory<>(setInit);

        SFormsFastMapDirect firstmap = createFirstMap(mt);
        extraVarVersions.put(dgraph.first.id, firstmap);

        setCatchMaps(root, dgraph, flatthelper);

        HashSet<String> updated = new HashSet<>();
        do {
            // System.out.println("~~~~~~~~~~~~~ \r\n"+root.toJava());
            ssaStatements(dgraph, updated);
            // System.out.println("~~~~~~~~~~~~~ \r\n"+root.toJava());
        }
        while (!updated.isEmpty());
    }

    private void ssaStatements(DirectGraph dgraph, HashSet<String> updated) {

        // try {
        // DotExporter.toDotFile(dgraph, new File("c:\\Temp\\gr1_my.dot"));
        // } catch(Exception ex) {ex.printStackTrace();}

        for (DirectNode node : dgraph.nodes) {

            //			if (node.id.endsWith("_inc")) {
            //				System.out.println();
            //
            //				try {
            //					DotExporter.toDotFile(dgraph, new File("c:\\Temp\\gr1_my.dot"));
            //				} catch (Exception ex) {
            //					ex.printStackTrace();
            //				}
            //			}

            updated.remove(node.id);
            mergeInVarMaps(node, dgraph);

            SFormsFastMapDirect varmap = inVarVersions.get(node.id);
            varmap = new SFormsFastMapDirect(varmap);

            SFormsFastMapDirect[] varmaparr = new SFormsFastMapDirect[]{varmap, null};

            if (node.exprents != null) {
                for (Exprent expr : node.exprents) {
                    processExprent(expr, varmaparr);
                }
            }

            if (varmaparr[1] == null) {
                varmaparr[1] = varmaparr[0];
            }

            boolean this_updated = !mapsEqual(varmaparr[0], outVarVersions.get(node.id))
                    || (outNegVarVersions.containsKey(node.id) && !mapsEqual(varmaparr[1], outNegVarVersions.get(node.id)));

            if (this_updated) {
                outVarVersions.put(node.id, varmaparr[0]);
                if (dgraph.mapNegIfBranch.containsKey(node.id)) {
                    outNegVarVersions.put(node.id, varmaparr[1]);
                }

                for (DirectNode nd : node.succs) {
                    updated.add(nd.id);
                }
            }
        }
    }

    private void processExprent(Exprent expr, SFormsFastMapDirect[] varmaparr) {

        if (expr == null) {
            return;
        }

        VarExprent varassign = null;
        boolean finished = false;

        switch (expr.type) {
            case Exprent.EXPRENT_ASSIGNMENT:
                AssignmentExprent assexpr = (AssignmentExprent) expr;
                if (assexpr.getCondType() == AssignmentExprent.CONDITION_NONE) {
                    Exprent dest = assexpr.getLeft();
                    if (dest.type == Exprent.EXPRENT_VAR) {
                        varassign = (VarExprent) dest;
                    }
                }
                break;
            case Exprent.EXPRENT_FUNCTION:
                FunctionExprent func = (FunctionExprent) expr;
                switch (func.getFuncType()) {
                    case FunctionExprent.FUNCTION_IIF:
                        processExprent(func.getLstOperands().get(0), varmaparr);

                        SFormsFastMapDirect varmapFalse;
                        if (varmaparr[1] == null) {
                            varmapFalse = new SFormsFastMapDirect(varmaparr[0]);
                        } else {
                            varmapFalse = varmaparr[1];
                            varmaparr[1] = null;
                        }

                        processExprent(func.getLstOperands().get(1), varmaparr);

                        SFormsFastMapDirect[] varmaparrNeg = new SFormsFastMapDirect[]{varmapFalse, null};
                        processExprent(func.getLstOperands().get(2), varmaparrNeg);

                        mergeMaps(varmaparr[0], varmaparrNeg[0]);
                        varmaparr[1] = null;

                        finished = true;
                        break;
                    case FunctionExprent.FUNCTION_CADD:
                        processExprent(func.getLstOperands().get(0), varmaparr);

                        SFormsFastMapDirect[] varmaparrAnd = new SFormsFastMapDirect[]{new SFormsFastMapDirect(varmaparr[0]), null};

                        processExprent(func.getLstOperands().get(1), varmaparrAnd);

                        // false map
                        varmaparr[1] = mergeMaps(varmaparr[varmaparr[1] == null ? 0 : 1], varmaparrAnd[varmaparrAnd[1] == null ? 0 : 1]);
                        // true map
                        varmaparr[0] = varmaparrAnd[0];

                        finished = true;
                        break;
                    case FunctionExprent.FUNCTION_COR:
                        processExprent(func.getLstOperands().get(0), varmaparr);

                        SFormsFastMapDirect[] varmaparrOr =
                                new SFormsFastMapDirect[]{new SFormsFastMapDirect(varmaparr[varmaparr[1] == null ? 0 : 1]), null};

                        processExprent(func.getLstOperands().get(1), varmaparrOr);

                        // false map
                        varmaparr[1] = varmaparrOr[varmaparrOr[1] == null ? 0 : 1];
                        // true map
                        varmaparr[0] = mergeMaps(varmaparr[0], varmaparrOr[0]);

                        finished = true;
                }
        }

        if (finished) {
            return;
        }

        List<Exprent> lst = expr.getAllExprents();
        lst.remove(varassign);

        for (Exprent ex : lst) {
            processExprent(ex, varmaparr);
        }

        SFormsFastMapDirect varmap = varmaparr[0];

        if (varassign != null) {

            Integer varindex = varassign.getIndex();

            if (varassign.getVersion() == 0) {
                // get next version
                Integer nextver = getNextFreeVersion(varindex);

                // set version
                varassign.setVersion(nextver);

                setCurrentVar(varmap, varindex, nextver);
            } else {
                setCurrentVar(varmap, varindex, varassign.getVersion());
            }
        } else if (expr.type == Exprent.EXPRENT_VAR) {

            VarExprent vardest = (VarExprent) expr;
            Integer varindex = vardest.getIndex();
            FastSparseSet<Integer> vers = varmap.get(varindex);

            int cardinality = vers.getCardinality();
            if (cardinality == 1) { // == 1
                // set version
                Integer it = vers.iterator().next();
                vardest.setVersion(it);
            } else if (cardinality == 2) { // size > 1
                Integer current_vers = vardest.getVersion();

                VarVersionPair currpaar = new VarVersionPair(varindex, current_vers);
                if (current_vers != 0 && phi.containsKey(currpaar)) {
                    setCurrentVar(varmap, varindex, current_vers);
                    // update phi node
                    phi.get(currpaar).union(vers);
                } else {
                    // increase version
                    Integer nextver = getNextFreeVersion(varindex);
                    // set version
                    vardest.setVersion(nextver);

                    setCurrentVar(varmap, varindex, nextver);
                    // create new phi node
                    phi.put(new VarVersionPair(varindex, nextver), vers);
                }
            } // 0 means uninitialized variable, which is impossible
        }
    }

    private Integer getNextFreeVersion(Integer var) {
        Integer nextver = lastversion.get(var);
        if (nextver == null) {
            nextver = 1;
        } else {
            nextver++;
        }
        lastversion.put(var, nextver);
        return nextver;
    }

    private void mergeInVarMaps(DirectNode node, DirectGraph dgraph) {

        SFormsFastMapDirect mapNew = new SFormsFastMapDirect();

        for (DirectNode pred : node.preds) {
            SFormsFastMapDirect mapOut = getFilteredOutMap(node.id, pred.id, dgraph, node.id);
            if (mapNew.isEmpty()) {
                mapNew = mapOut.getCopy();
            } else {
                mergeMaps(mapNew, mapOut);
            }
        }

        if (extraVarVersions.containsKey(node.id)) {
            SFormsFastMapDirect mapExtra = extraVarVersions.get(node.id);
            if (mapNew.isEmpty()) {
                mapNew = mapExtra.getCopy();
            } else {
                mergeMaps(mapNew, mapExtra);
            }
        }

        inVarVersions.put(node.id, mapNew);
    }

    private SFormsFastMapDirect getFilteredOutMap(String nodeid, String predid, DirectGraph dgraph, String destid) {

        SFormsFastMapDirect mapNew = new SFormsFastMapDirect();

        if (nodeid.equals(dgraph.mapNegIfBranch.get(predid))) {
            if (outNegVarVersions.containsKey(predid)) {
                mapNew = outNegVarVersions.get(predid).getCopy();
            }
        } else if (outVarVersions.containsKey(predid)) {
            mapNew = outVarVersions.get(predid).getCopy();
        }

        boolean isFinallyExit = dgraph.mapShortRangeFinallyPaths.containsKey(predid);

        if (isFinallyExit && !mapNew.isEmpty()) {

            SFormsFastMapDirect mapNewTemp = mapNew.getCopy();

            SFormsFastMapDirect mapTrueSource = new SFormsFastMapDirect();

            String exceptionDest = dgraph.mapFinallyMonitorExceptionPathExits.get(predid);
            boolean isExceptionMonitorExit = (exceptionDest != null && !nodeid.equals(exceptionDest));

            HashSet<String> setLongPathWrapper = new HashSet<>();
            for (FinallyPathWrapper finwraplong : dgraph.mapLongRangeFinallyPaths.get(predid)) {
                setLongPathWrapper.add(finwraplong.destination + "##" + finwraplong.source);
            }

            for (FinallyPathWrapper finwrap : dgraph.mapShortRangeFinallyPaths.get(predid)) {
                SFormsFastMapDirect map;

                boolean recFinally = dgraph.mapShortRangeFinallyPaths.containsKey(finwrap.source);

                if (recFinally) {
                    // recursion
                    map = getFilteredOutMap(finwrap.entry, finwrap.source, dgraph, destid);
                } else {
                    if (finwrap.entry.equals(dgraph.mapNegIfBranch.get(finwrap.source))) {
                        map = outNegVarVersions.get(finwrap.source);
                    } else {
                        map = outVarVersions.get(finwrap.source);
                    }
                }

                // false path?
                boolean isFalsePath;

                if (recFinally) {
                    isFalsePath = !finwrap.destination.equals(nodeid);
                } else {
                    isFalsePath = !setLongPathWrapper.contains(destid + "##" + finwrap.source);
                }

                if (isFalsePath) {
                    mapNewTemp.complement(map);
                } else {
                    if (mapTrueSource.isEmpty()) {
                        if (map != null) {
                            mapTrueSource = map.getCopy();
                        }
                    } else {
                        mergeMaps(mapTrueSource, map);
                    }
                }
            }

            if (isExceptionMonitorExit) {

                mapNew = mapTrueSource;
            } else {

                mapNewTemp.union(mapTrueSource);

                SFormsFastMapDirect oldInMap = inVarVersions.get(nodeid);
                if (oldInMap != null) {
                    mapNewTemp.union(oldInMap);
                }

                mapNew.intersection(mapNewTemp);
            }
        }

        return mapNew;
    }

    private static SFormsFastMapDirect mergeMaps(SFormsFastMapDirect mapTo, SFormsFastMapDirect map2) {

        if (map2 != null && !map2.isEmpty()) {
            mapTo.union(map2);
        }

        return mapTo;
    }

    private static boolean mapsEqual(SFormsFastMapDirect map1, SFormsFastMapDirect map2) {

        if (map1 == null) {
            return map2 == null;
        } else if (map2 == null) {
            return false;
        }

        if (map1.size() != map2.size()) {
            return false;
        }

        for (Entry<Integer, FastSparseSet<Integer>> ent2 : map2.entryList()) {
            if (!InterpreterUtil.equalObjects(map1.get(ent2.getKey()), ent2.getValue())) {
                return false;
            }
        }

        return true;
    }

    private void setCurrentVar(SFormsFastMapDirect varmap, Integer var, Integer vers) {
        FastSparseSet<Integer> set = factory.spawnEmptySet();
        set.add(vers);
        varmap.put(var, set);
    }

    private void setCatchMaps(Statement stat, DirectGraph dgraph, FlattenStatementsHelper flatthelper) {

        SFormsFastMapDirect map;

        switch (stat.type) {
            case Statement.TYPE_CATCHALL:
            case Statement.TYPE_TRYCATCH:

                List<VarExprent> lstVars;
                if (stat.type == Statement.TYPE_CATCHALL) {
                    lstVars = ((CatchAllStatement) stat).getVars();
                } else {
                    lstVars = ((CatchStatement) stat).getVars();
                }

                for (int i = 1; i < stat.getStats().size(); i++) {
                    int varindex = lstVars.get(i - 1).getIndex();
                    int version = getNextFreeVersion(varindex); // == 1

                    map = new SFormsFastMapDirect();
                    setCurrentVar(map, varindex, version);

                    extraVarVersions.put(dgraph.nodes.getWithKey(flatthelper.getMapDestinationNodes().get(stat.getStats().get(i).id)[0]).id, map);
                }
        }

        for (Statement st : stat.getStats()) {
            setCatchMaps(st, dgraph, flatthelper);
        }
    }

    private SFormsFastMapDirect createFirstMap(StructMethod mt) {
        boolean thisvar = !mt.hasModifier(CodeConstants.ACC_STATIC);

        MethodDescriptor md = MethodDescriptor.parseDescriptor(mt.getDescriptor());

        int paramcount = md.params.length + (thisvar ? 1 : 0);

        int varindex = 0;
        SFormsFastMapDirect map = new SFormsFastMapDirect();
        for (int i = 0; i < paramcount; i++) {
            int version = getNextFreeVersion(varindex); // == 1

            FastSparseSet<Integer> set = factory.spawnEmptySet();
            set.add(version);
            map.put(varindex, set);

            if (thisvar) {
                if (i == 0) {
                    varindex++;
                } else {
                    varindex += md.params[i - 1].stackSize;
                }
            } else {
                varindex += md.params[i].stackSize;
            }
        }

        return map;
    }

    public HashMap<VarVersionPair, FastSparseSet<Integer>> getPhi() {
        return phi;
    }
}
